Clozapine is an atypical neuroleptic: it does not affect dopamine (DA) neuronal function in the same way as typical neuroleptics, which may explain why clozapine produces relatively few extrapyramidal side effects. To gain better insight on how these two classes of neuroleptics influence central DA metabolism, we compared DA turnover and release following acute and chronic doses of clozapine and haloperidol. DA turnover was assessed from changes in the concentrations of the DA metabolites; 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). DA release was assessed from the rate of accumulation of 3-methoxytyramine (3MT) after the administration of a high dose of pargyline, a potent monoamine oxidase inhibitor. Three brain regions were studied: the frontal cortex, nucleus accumbens and caudate nucleus.